We had had early access to Hearthstone's new adventure, Awakening of Galakrond, which adds two story campaigns for the player to follow. The adventure itself is divided into four chapters, and each campaign - one from the League of Evil, the other from the League of Explorers - has three bosses. This means that each chapter includes six bosses, both in normal and heroic modes.
To win the exclusive cards of the adventure you only need to defeat the bosses in normal mode with Blizzard's default deck, but if you're looking for an extra challenge, you can try to defeat the bosses in heroic mode with your own deck. That's what we did in the videos below, first defeating the first boss of each campaign in normal mode and then in heroic mode, with the default Warrior pirate deck.
P.S. All the cards in the Warrior deck are golden as this is Blizzard's special account.
Normal
Heroic